The field of the present invention is flow shutoff valves for residential water line pressure.
Shutoff valves to prevent excess flow, such as when a sudden leak occurs downstream of the valve, are well known in the art. Such valves are found in high pressure hydraulic systems, fueling systems and critical gas systems. Such valves are relatively expensive because of complicated housings and/or valve elements, the materials, and their precision machining requirements.
Household appliances which use water such as a washing machine are most often connected to manual shutoff valves which are installed in the home. The conventional means for connecting the manual shutoff valves to an appliance are typically through flexible hoses. Personal experience and insurance statistics suggest that a great many such manual shutoff valves are not closed when the appliance is not in use. Consequently, the integrity of the flexible hoses remains the only means of containing a household system water pressure to an appliance. Insurance companies in North America report payments amounting to hundreds of millions of dollars annually which solely result from broken household appliance hoses.
The shutoff valves used for hydraulics, fuels and gasses are out of practical range for use with home appliances. However, other solutions have been applied to the problem of residential flooding from appliance hoses in a number of ways. Electrical sensors, timers and valve drives have been devised. Mechanical devices have also been employed which are complicated, expensive and/or limited in their use.
One problem which must be addressed by shutoff devices for residential use is the presence of particles and hardness in the water supply which can accumulate to disable such valves. The utility of most shutoff valves is as an emergency device with very infrequent actuation. Consequently, interfering deposits can be built up with continued flow through the valve without actuation and result in malfunction of the valve when needed.